Multiple parameter monitoring in a direct methanol fuel cell

Direct methanol fuel cells (DMFCs) are promising candidates for energy supply based on renewable sources. They provide a high power density and the possibility of an easy recharge. Moreover, the fuel storage is significantly easier than it is for hydrogen fuel cells. However, in continuous operation, supplying the anode with a constant concentration of methanol is the key to achieving stable and optimal performance. Hence, developing a method for measuring the methanol content of the fuel online is desirable for advanced monitoring of the fuel cell. In this work, we report the combined application of Raman spectroscopy, chronoamperometry and gravimetry for the simultaneous determination of the methanol concentration and the Faradaic efficiency in a DMFC. Raman spectroscopy is used to measure the actual methanol concentration supplied to the anode. The chronoamperometric and gravimetric measurements allow the theoretical methanol concentration, i.e. assuming that methanol is only consumed by electro-oxidation, to be determined. The full set of data ultimately facilitates the calculation of the Faradaic efficiency.